In rotating electric mechanisms such as industrial or vehicle motors, it is required to realize high torque, low cogging, a wide operation range, and the like. As a technique to meet such requirements, for example, a rotor for a rotating electric mechanism is disclosed which has a rotor core having permanent magnets embedded near the outer circumference thereof and having air gap holes formed at the outer circumference side with respect to the permanent magnets such that the position in the circumferential direction of the air gap holes is different depending on a position in the axial direction. Since the air gap holes are located at positions different in the circumferential direction, the respective cogging torques are cancelled by each other, and thus cogging torque is suppressed (for example, see Patent Document 1).
Another rotating electric mechanism is disclosed which has a plurality of rotor cores each having a permanent magnet insertion hole that is symmetric in the circumferential direction, and having, at both ends of the insertion hole, openings that are asymmetric with each other in the circumferential direction, the plurality of rotor cores being alternately inverted and integrally attached in the axial direction to form a single rotor core (for example, see Patent Document 2).